EARTH

[3901-12-05] Leaching behavior of metal-organic chemical vapor deposition (MOCVD) waste of GaN

○Li-Lin Hsu¹, Wei-Sheng Chen¹ (1. National Cheng Kung University)

Chairman: Kyoungkeun Yoo （Korea Maritime and Ocean University）, Naoki Hiroyoshi (Hokkaido University)

Keywords:Gallium Nitride, Gallium, Indium, Hydrometallurgy, Resources Recovery

In this study , a metal-organic chemical vapor deposition (MOCVD) waste of GaN based power device and LED industry is investigated by acid leaching. The laureates of the Nobel Prize in Physics, Nakamura Shuji, Isamu Akasaki and Hiroshi Amano, did the research about gallium nitride (GaN) doping indium and aluminum and invented the efficient blue light-emitting diodes (Blue LED). This invention was also called as the second lighting revolution because it enabled bright and energy-saving white light sources. As the research of blue LED increased in recent years, the development of white LED has become no longer dreaming. For the adaptation of this great impact and the market variation, the resources of gallium and indium will become a major issue of this lighting revolution. This study will focus on the leaching behavior of GaN-containing wastes by using different acids. Various leaching process parameters like effect of acidity, solid-liquid ratio, temperature and concentration of acids on the leaching efficiency of gallium and indium are investigated.Because the refractory GaN phase is hard to leach, using pyrometallurgy like high temperature oxidative roasting and thermal diffusion for the pre-treatment of the wastes. Combined with hydrometallurgy, such as acid leaching and the process is optimized by ICP-AES analysis.The effective optimum condition for quantitative leaching of gallium and indium is investigated.